Many types of construction implements, forestry vehicles, and other work vehicles include an operator's seat assembly that rotates between multiple operational positions to give the operator flexibility in performing tasks with the work vehicle. For example, a work vehicle may have front and rear implements, and the operator rotates his seat from a front-facing position for operating the front implement to a rear-facing position for operating the rear implement. To satisfy regulatory standards, it may be required to provide certain HVAC functionality within the vehicle cabin depending on the operational position of the seat. For example, International Organization for Standardization (ISO) standard 10263-5 requires an earth-moving vehicle that can be operated with the seat facing frontward or rearward to have defroster functionality for both the front and rear windscreens. Operator comfort is also a concern: it is desirable for the HVAC system to blow air onto the operator regardless of the seat position.
To account for all operational positions of the seat, HVAC systems for such work vehicles may be designed to provide all functionality for all seat positions at all times. Such an overbuilt system is unnecessarily complex and expensive, and is inefficient due to its provision of HVAC functionality where it is not needed. In other systems, the operator may need to manually adjust the HVAC controls when he moves the seat between operational positions. This is also inefficient, adds labor and risk of distraction, and may cause unsafe conditions if the operator does not properly adjust the controls. An HVAC control system that electronically and automatically adjusts the HVAC functionality depending on the operational position of the seat is needed.